By formulating a general theory of the topological aspects of the Friedel sum rule that
incorporates the effects of broken channel and spin symmetries, fully corroborated by numerical
calculations for a model Hamiltonian, we reliably established that FePc on Au(111) behaves as a
NLFL. With a single set of parameters we explained three key experiments on the differential
conductance of this system [1]}, [2]}, [3]}. The sole assumption (i.e., that the scanning tunneling
microscope senses mainly the 3d orbital of Fe with \(3d^2-r^2\)  symmetry) is simple, physically realistic, and consistent with ab initio calculations [4]}
